Spray foams are widely used as building insulation materials due to their excellent thermal insulation, fire resistance, and mechanical properties. The foams are commonly grouped as either “open cell” foams or “closed cell” foams depending on whether the cells in the foam are completely closed. Spray polyurethane foams (SPFs) made from polyurethane (PUR) are used in both open cell and closed cell foams, while spray isocyanurate foams are made from polyisocyanurate (PIR) and is normally used to make dense closed cell foams.
Spray foam insulation is often formed as the polymerizing reactants are being sprayed directly into the building envelope to be insulated, usually with the help of a blowing agent. In order to pass the fire tests required by modern building codes, such as the ASTM E-84 test, additional fire retardants are commonly added to the PUR and PIR formulations. These fire retardants may include non-reactive, halogenated fire retardants such a tris(1-chloro-2-propyl) phosphate or TCPP, which imparts increased fire resistance to the foams by generating both gas-phase, radical scavenging chlorine groups, as well as forming a char that is difficult for flames to penetrate.
More recently, non-reactive halocarbons like TCPP have come under scrutiny for health and envirornmental reasons. Unlike reactive halogenated fire retardants that react with and stay bound to the polymer matrix of the spray foam, non-reactive halogenated fire retardants can escape from the spray foam over time and become an airborne pollutant. Consequently, there has been an increased effort to reduce or eliminate the use of non-reactive halogenated compounds as fire retardants in furniture, fabrics and building insulation. The reduction in the use of TCPP and other non-reactive halogenated fire retardants has made it more challenging for PUR and PIR foams to pass modern fire tests, necessitating the need for new formulations with enhanced fire resistance that only use reactive halogen flame retardants and/or non-halogen containing flame retardants. The present application describes such formulations and their use in foams for building insulation and other articles.